1. Field of the Invention
The present invention relates to a semiconductor device for controlling a power semiconductor element to which a high voltage of several hundred volts is applied.
2. Background Art
As a kind of semiconductor device for controlling a power semiconductor element to which a high voltage of several hundred volts is applied, a device is known that has a low-potential signal processing circuit and a high-potential signal processing circuit, and that realizes signal transmission by means of an alternating current electric field between the low-potential signal processing circuit and the high-potential signal processing circuit connected to each other through a capacitor, between which a large potential difference is produced. In such a conventional semiconductor device, the low-potential signal processing circuit and the high-potential signal processing circuit are formed in separate chips: a chip on the low-voltage side and a chip on the high-voltage side. The capacitor is formed by an interlayer insulating film formed on the chip on the high-voltage side and electrodes sandwiching the interlayer insulating film. The low-potential signal processing circuit and the capacitor are connected to each other by a wire (see, for example, U.S. Pat. No. 6,873,065).